of Metals for reflecting ti’elef copes. 331 
When the polifh of the metal nearly reaches the 
edge (for it always, as I faid before, begins in the mid- 
dle) you muft alter your method of working; for’ now 
the round ftrokes muft be gradually altered for the 
Ihort and ftraight ones. Supposing then you are juft 
beginning to alter them ; after having put on frefh putty, 
and gently rubbed it with two or three ftrokes of tiie 
bruifer, you place the metal on the tool, and after a ftroke 
or two round and round, give it a few forward and back- 
ward, and from ftde to fide, but with the edges very little 
over the tool; then having turned the metal one-eighth 
round in your hand, and having moved yourfelf as much 
round the block (which muft be remembered throughout 
the whole procefs) you go on again with a ftroke or two 
round, to lead you only to the crofs ftrokes, which are 
now to be principally ufed, and with more boldnefs. 
After this has been done fome time, the metal will begin 
to move ftiffly as the friftion now increafes, and the fpe- 
culum polifhes very beautifully arid faft ; and the whole 
furface of the polifhing tool will be equally covered over 
with a fine metallic bronze. The tool even now muft 
not be fuffered to become dry ; a fingle round ftroke in 
each of your ftations and turnings of the metal will 
be fufficient, and the reft muft all be crofs ones, for we 
are completing a circular figure. You muft now be very 
U u 2 diligent, 
